JP2000131755A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb the energy of the returning action of a movable mirror to a position where it abuts on a regulation member by energizing force for relaxing colli sion and to enable not only the first rebounding of the movable mirror to be reduced just after it collides with the regulation member and but also the fine vibration thereof just after the first rebounding to be suppressed by pressing energizing force. SOLUTION: This camera is constituted so that the movable mirrors 2 and 11 made to abut on the regulation member and positioned in a photographing optical path are retreated outside the photographing optical path at a finder observation time and returned to the position where they abut on the regulation member by the driving energizing force of a driving means after a photographing is finished. Besides, it is provided with an assistance means making the energizing force act on the movable mirrors so that the movable mirrors are pressed to the position where they abut on the regulation member in addition to the driving energizing force of the driving means just before they abut on the regulation member and a collision relaxing means 60 making the energizing force for relaxing collision resisting to both of the above mentioned energizing force act on the movable mirrors by such magnitude that the returning actions of the movable mirrors are not obstructed just before they abut on the regulation member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a camera such as a single-lens reflex camera having a drive mechanism for a movable mirror that moves up and down in a mirror box.

[0002]

2. Description of the Related Art A single-lens reflex camera is provided with a movable mirror which is inclined in a photographing optical path during viewfinder observation and which can move up and down in a mirror box so as to retreat outside the photographing optical path during photographing. Then, the movable mirror is driven downward from the retracted position to the oblique position by the spring force, and is positioned at the oblique position by contacting the regulating member. In this case, the movable mirror driven by the spring force collides with the regulating member, so that at least a so-called bouncing phenomenon occurs in which the movable mirror rebounds greatly at the time of the collision and then repeats the fine vibration.

[0003] The above-mentioned bouncing phenomenon has a remarkable effect on the viewfinder and the like as the camera has a higher continuous shooting speed. Further, the movable mirror is provided with an auxiliary mirror (hereinafter, referred to as a sub-mirror) for a focus detection device. Recent cameras have a problem that the continuous shooting speed is limited because the focus cannot be detected immediately after the mirror descends due to the bouncing phenomenon.

[0004] Most of the sub-mirrors are mounted on a member that supports a movable mirror (hereinafter, referred to as a main mirror) for finder observation. Most of the sub-mirror bounce is suppressed by first suppressing the bounce phenomenon of the main mirror. Can be reduced.

[0005] Many proposals have been made to suppress the above-mentioned bouncing phenomenon. For example, Japanese Utility Model Laid-Open Publication No. 63-14194 proposes a method in which a regulating member has a biasing force for absorbing a shock. However,
If the restricting member is provided with a shock absorbing mechanism, it is difficult to stably maintain the movable mirror at the inclined position.

Japanese Unexamined Patent Publication No. 6-75296 discloses a method of lowering the movable mirror by contacting a contact surface provided on a guide lever which rotates substantially simultaneously with the lowering operation of the movable mirror. There have been proposals for limiting the speed to achieve a shock absorbing effect.

[0007]

However, according to the method proposed in Japanese Patent Laid-Open No. 6-75296, the operation timing of the movable mirror that moves down only by the spring force and the guide lever that uses the motor as a drive source. Is not used, and there is no guarantee that the movable mirror will surely contact the contact surface. In particular, when the frame speed is extremely high, the operation of the guide lever driven by the motor becomes extremely fast, sometimes exceeding the lowering speed of the movable mirror determined only by the urging force of the spring.

Further, even if the descending speed of the movable mirror is reduced, a slight vibration remains after the collision with the regulating member.
The viewfinder or the focus detection device continues to be affected until the end of the micro-vibration, resulting in a problem that the continuous shooting speed of the camera cannot be increased.

Therefore, in a camera that desires to improve the continuous shooting speed, it is necessary to provide a mechanism having means for surely suppressing the rebound of the movable mirror for the first time and suppressing bouncing phenomena so as not to cause micro vibration thereafter.

[0010]

Therefore, according to the present invention, the movable mirror, which has been positioned in the photographing optical path by contacting the regulating member during viewfinder observation, is retracted out of the photographing optical path at the time of photographing. In a camera that is operated to return to a position where it contacts the regulating member by the driving urging force,
Immediately before contacting the regulating member, the movable mirror performing the returning operation is provided with assist means for applying a pressing urging force to a position contacting the regulating member in addition to the driving urging force of the driving means. Immediately before coming into contact with the regulating member, a collision-mitigating means for applying a collision-mitigating urging force acting against the above-mentioned urging forces with a size that does not hinder the return operation of the movable mirror is provided.

That is, by absorbing the energy of the return operation of the movable mirror by the collision-mitigating urging force, the first rebound immediately after the movable mirror comes into contact with the regulating member (collision) is reduced, and the movable mirror is moved by the pressing urging force. It is configured to suppress micro-vibration that occurs after the mirror bounces.

In the above arrangement, after the movable mirror comes into contact with the regulating member by the return operation, the collision easing means is moved to a position where the movable mirror is separated from the regulating member, and when the movable mirror retreats outside the photographing optical path. It is desirable that the movable mirror be moved to a position where it can come into contact with the movable mirror that performs the return operation, so that the positioning of the movable mirror after the completion of the return operation at the position that comes into contact with the restricting member is assured.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) First, in a camera according to a first embodiment of the present invention, a movable mirror which moves up and down between a viewfinder observation and a photographing operation in a mirror box by a mirror driving mechanism is provided. The mirror unit including the mirror unit will be described.

FIG. 21 shows a position where the movable mirror is obliquely provided in the photographing optical path for viewfinder observation or standby (hereinafter, referred to as a position where the movable mirror is inclined).
(Referred to as a down position). FIG. 22 shows a mirror-up state in which the movable mirror is retracted outside the imaging optical path for imaging (hereinafter, referred to as an up position).

In FIG. 21, reference numeral 2 denotes a main mirror having a semi-transmissive area, and a light beam from an objective lens (not shown) attached to a mount 54 is focused on a focusing plate 50 and an optical axis 1.
In the direction of.

Reference numeral 11 denotes a main mirror receiving plate for fixing the main mirror 2, which is rotatably supported by a link 20. The main mirror receiving plate 11 has an opening 11d for passing the light beam transmitted through the main mirror 2 to the sub mirror 3.
Is provided. Behind the main mirror receiving plate 11,
A sub-mirror 3 having a reflecting surface 3a is provided obliquely.
1

A sub-mirror receiving plate 16 for fixing the sub-mirror 3 is rotatably supported on the main mirror receiving plate 11. Note that the entire unit composed of the two mirrors 2 and 3, the main mirror receiving plate 11, the sub mirror receiving plate 16, and the link 20 is hereinafter referred to as a mirror unit.

The mirror unit is rotatably mounted in the mirror box by supporting a rotation shaft 20b of the link 20. Further, a light shielding plate 52 is provided obliquely below the mirror box so as to cover the light entrance 51a of the focus detection device 51. The light shielding plate 52 prevents harmful light from entering the focus detection device 51.

In the photographing state of the camera shown in FIG. 22, the mirror unit is retracted out of the photographing optical path immediately below the focusing plate 50 so as to be folded, and covers the focusing plate 50. Further, the light-shielding plate 52 is also retracted to the outside of the photographing optical path and closes the light entrance 51a of the focus detection device.

Next, details of the mirror unit will be described with reference to FIGS. 15 is a side view of the mirror unit viewed from the same direction as FIG. 21, FIG. 16 is a side view of the mirror unit viewed from the opposite side of FIG. 15, and FIG. 17 is a plan view showing the entire configuration of the mirror unit. 18 is a plan view showing the configuration of the sub mirror receiving plate.

The main mirror receiving plate 11 shown in FIG.
The main mirror 2 is attached to the front side of the drawing sheet using a silicone adhesive or the like. A light-shielding sheet 15 is attached to one end of the opening 11d of the main mirror receiving plate 11, and as shown in FIG. 22, a portion where harmful light from the finder cannot be completely blocked by the sub-mirror unit of the opening 11d in a mirror-up state. Passing through to the imaging surface 53 is prevented.

Further, a right main mirror arm 13 to which a main mirror hinge shaft 13a and a main mirror driving pin 13b are fixed is provided on both left and right ends of the main mirror receiving plate 11.
And the left main mirror arm 14 to which the main mirror hinge shaft 14a and the sub mirror hinge shaft 14b are fixed. Also, relatively high hardness buffer rubbers 11e are attached to the back side of the paper at both ends of the main mirror tip. Note that, of the mirror units, a unit configured around the main mirror receiving plate 11 is hereinafter referred to as a main mirror unit.

Each of the main mirror hinge shafts 13a and 14a has a sub-mirror drive pin 20a and a link drive pin 20c.
A U-shaped link 20 to which is attached is attached. If one of the left and right main mirror arms 13 and 14 and the main mirror receiving plate 11 are fastened with screws or the like, the link 20 can be easily removed.

The sub-mirror 3 in which the reflecting portion 3a and the flange portion 3b are integrally formed is attached to the sub-mirror receiving plate 16 with a double-sided tape or the like. Further, on the front side of the sub-mirror 3, a sub-mirror mask 18 having an opening in the reflecting portion 3a of the sub-mirror 3 is attached. One end of the sub mirror receiving plate 16 has sub mirror driving cams 17a,
The sub-mirror driving plate 17 on which 7b is formed is fastened. The sub-mirror receiving plate 1 of the mirror unit
The unit composed mainly of 6 is hereinafter referred to as a sub-mirror unit.

This sub-mirror unit is supported by the main mirror unit by a screw 12 via a sub-mirror hinge shaft 14b and a collar 21, and the sub-mirror driving cam 1
7a and 17b are sub-mirror drive pins 20a of the link 20
(In the mirror-down state, the sub-mirror driving cams 17a and 17b are separated from the mirror driving pin 20a). Further, the sub-mirror unit is urged in the opening direction (counterclockwise in FIG. 15) with respect to the main mirror unit by the sub-mirror spring 19 attached to the sub-mirror hinge shaft 14b.

Each mirror 2, 3 in the mirror down state
Is properly maintained by the adjusting dowels 6 and 7 which are cylindrical regulating members provided on the opposing side walls in the mirror box.

In the main mirror unit supporting the main mirror 2, the cushion rubber 11 e is in contact with the adjusting dowel 6, and in the sub mirror unit supporting the sub mirror 3, the tip of the sub mirror driving plate 17 is in contact with the adjusting dowel 7. In addition, any adjustment dowel can finely adjust the contact position with the mirrors 2 and 3 by an eccentric mechanism or the like. The mirror unit moves up and down when the main mirror drive pin 13b and the link drive pin 20c receive an operation of a mirror drive unit described later.

Next, a series of operations of the camera according to the present embodiment from the mirror down state to the mirror up state and back to the viewfinder observation state will be described in order.

FIG. 1 is a schematic view of the mirror box 4 as viewed from the front of the camera. With the mirror unit 71 in the mirror box 4 interposed, on the left of the mirror box 4,
Mirror drive unit 7 including drive means according to the claims
0 is mounted, and a buffer mechanism 72 including a buffer lever 60 which constitutes a collision mitigation means is mounted on the opposite side of the mirror box 4 opposed thereto.

The buffer lever 60 has a mirror contact portion 60a protruding into the mirror box like the adjustment dowel 6, and can contact the main mirror 11.
In addition, a light shielding plate 52 is attached to a lower portion of the mirror box 4 from the mirror driving unit 70 to the buffer mechanism 72.

FIG. 2 is a plan view showing the mirror driving unit 70 when the camera is in the mirror down state.
The mirror drive unit 70 is configured by the following components attached to a base plate (not shown).

A shaft 31a shown substantially at the center of the figure is provided with a moving lever 31 for controlling the operation of the mirror driving unit 70 and a first mirror lever 32 which is one of the members constituting the driving means. Supported.

The pushing lever 31 is urged in the clockwise direction in the figure by a pushing spring 34 which is a tension spring. However, this raising lever 31 is raised by engaging the bending portion 31c with the tightening portion 35a of the up tightening lever 35 which is urged in the counterclockwise direction by a spring (not shown).
It is held in the state shown.

The first mirror lever 32 is urged counterclockwise with respect to the power lever 31 by a mirror drive lever spring 45. However, the first mirror lever 32
Is stopped in the state shown in the figure because the light-shielding plate drive pin 32b fixed to one end abuts on a part of the base plate (not shown).

A down tensioning lever 36 is pivotally supported by the lever 31 and a tensioning portion 36a urged clockwise by a spring (not shown) is provided with a first mirror lever 3.
The second stand-by portion 32c is in a standby state in which it can be engaged.

As shown in the upper left part of the figure, a second mirror lever 33, which is another member constituting the driving means, is pivotally supported on the main plate. The above-mentioned main mirror drive pin 13b is engaged with the connection groove 33c provided at the tip of the second mirror lever 33 in a substantially fitted state via the mirror drive collar 13c. For this reason, the second mirror lever 33
Is rotatable with the elevation of the main mirror unit.

A second mirror lever driving shaft 33a fixed to the second mirror lever 33 has a mirror down spring 37, which is another member constituting the driving means, hooked thereon. Urges the main mirror unit in the mirror-down direction via the drive force.

Further, above the second mirror lever 33,
A link drive cam 33d that can contact the link pin 20c is formed. However, in the mirror-down state, the two do not contact each other, and the link 20 receives the urging force of the link spring 38, and the link drive pin 20c contacts the precision surface of the base plate.
Holds the mirror down state.

Reference numeral 39 denotes an assist lever constituting an assist means referred to in the claims, which is urged in a counterclockwise direction by an urging force of an assist spring 40 which is another member constituting the assist means.

At one end of the assist lever 39, there are formed charge cam portions 39a and 39b which can abut a charge pin 31b fixed to the power lever 31. In the mirror down state, the assist lever 39 is held in the state shown in the figure against the urging force of the assist spring 40 when the cam top portion 39a comes into contact with the charge pin 31b. Also,
A guide groove 39c is provided on the assist lever 39 on the side opposite to the charge cam portion 39a, and a part thereof is a hook portion 39d. The second mirror lever drive shaft 33a enters into the guide groove 39c. However, at the position of the assist lever 39 in the mirror down state,
Even if the second mirror lever 33 rotates, the second mirror lever shaft 33a does not catch on the hook 39d.

The tension release lever 40 and the armature lever 43 are substantially connected to each other by engaging portions 40a and 43b, and rotate together coaxially. Both levers 4
Although 0 and 43 receive a biasing force in the counterclockwise direction by the tension release spring 42, the armature 43a at one end of the armature lever 43 is held as shown in the drawing by being attracted to the electromagnet 44 having a permanent magnet. Have been.

The light shielding plate 52 is rotatable about a shaft 52b, and is urged clockwise by a light shielding plate spring 46. In the mirror-down state, the light-shielding plate 52 abuts against a stopper (not shown) on the mirror box and is held in the state shown in the figure. FIG. 3 is a plan view showing the buffer mechanism in the mirror down state. Buffer lever 6
0 has a substantially L-shape. One end is provided with a mirror contact portion 60a capable of contacting the buffer rubber 11e of the main mirror receiving plate 11, and the other end is provided with a cam contact portion 60b. Have been.

The buffer lever 60 is rotatable about a shaft 60c, and is urged clockwise by the urging force of a buffer spring 62 which is another member constituting the above-mentioned collision mitigation means.

A locking lever 61 is disposed below the buffer lever 60. The locking lever 61 is urged clockwise by a spring 63. In the mirror-down state, the cam portion 61a of the locking lever 61 comes into contact with the cam abutting portion 60b of the buffer lever 60, and the urging force of the locking lever 61 generates a moment for the buffer lever 60 to overcome the buffer spring 62. Let it. Thereby, the buffer lever 60
Is held in a state in which it abuts on the evacuation stopper 64, and the mirror contact portion 60a of the buffer lever 60 does not act on the main mirror unit at all.

Next, the operation of the mirror drive unit 70 and the buffer mechanism 72 during the operation of the mirror unit from the mirror-down state to the mirror-up state will be described in detail with reference to FIG. 2 and FIGS.

As shown in FIG. 2, when the electromagnet 44 is energized to lose the attraction force to the armature 43a, the tension release lever 40 is moved counterclockwise to the position 40 'by the urging force of the spring 42. To rotate. This tension release lever 4
0 pushes the up tension lever 35 by the contact portion 40b and rotates it clockwise to the position of 35 ', so that the tension portion 35a
Deviates from c. Livestock lever 31 released from the locked state
Starts rotating clockwise by the urging force of the stock spring 34, and the mirror drive unit 70 shifts to the state shown in FIG.

When the power lever 31 rotates clockwise, the first mirror lever 32 engaged with the down tension lever 36 also rotates together, and the transmission cam portion 32a moves the second mirror lever drive shaft. The second mirror lever 33 is pushed up by coming into contact with a roller 33b attached to the roller 33a. The second mirror lever 33, which rotates counterclockwise against the urging force of the mirror-down spring 37, raises the main mirror unit with the main mirror driving pin 13b engaged with the coupling groove 33c, and drives the link. The cam 33d contacts the link drive pin 20c to raise the link 20.

In the state shown in FIG.
The cam top portion 39a is still in contact with the charge pin 31b and the rotation is restricted, and the second mirror lever drive shaft 33b that moves in the guide groove 39c is hooked 39d.
Pass without restriction by.

The following operation is performed by the rotating moving lever 31 and the first mirror lever 32 in addition to the raising operation of the main mirror unit.

The arm-like cam portion 31d of the raising lever 31 pushes up the roller 40c attached to the tension release lever 40, and the tension release lever 40 and the armature lever 43 return. Further, the light-shielding plate drive pin 32b fixed to the tip of the first mirror lever 32 that rotates clockwise abuts on the cam portion 52a of the light-shielding plate 52, and starts the escaping operation of the light-shielding plate 52 from the photographing light beam. Let it.

FIG. 5 shows a mirror driving unit 70 in which the movement lever 31 and the first mirror lever 32 are further rotated.
The state of is shown. The raising operation of the main mirror unit and the retracting operation of the light shielding plate 52 are continuously performed, and the returning operation of the tension release lever 40 and the armature lever 43 is almost completed.

Reference numeral 47 denotes a mirror-up switch for the camera to detect the movement of the main mirror unit. In this state, the arm 20d of the link 20 which starts moving up starts pushing up the terminal of the mirror-up switch 47.

The charge pin 31b of the moving lever 31 that moves to the left in the figure is the cam top 3 of the assist lever 39.
9a, the rotation of the assist lever 39 is prevented by the second mirror lever drive shaft 33a which moves while abutting on the end face 39e of the guide groove 39c.

Here, the arc shape of the end surface 39e of the guide groove 39c is formed such that the center thereof coincides with the rotation center of the second mirror lever 33, and the second mirror lever 33
It does not hinder the rotation of.

Then, as shown in FIG.
The lifting operation of the main mirror unit is completed at the point when 1 hits the livestock stopper 46 attached to the main plate. The mirror up switch 47 is completely turned off to notify the camera control circuit (not shown) that the main mirror unit is at the up position.

The second mirror lever 33 is pushed up to the position of the cam top portion 32d of the first mirror lever 31.
The link drive pin 20c enters the link groove 33e of the second mirror lever 33 to prevent the link 20 from bouncing when the mirror has been raised. The assist lever 3
Reference numeral 9 keeps the position in the mirror down state.

FIG. 7 is a plan view showing the state of the buffer mechanism in the mirror-up state. The light-shielding plate 52 having a sufficient operating force based on the turning power of the livestock lever 31 is rotated by approximately 45 ° from the position of the mirror-down state, and attached to the side surface of the light-shielding plate 52 halfway through the rotation. Lock release pin 5
2c is brought into contact with the arm portion 61c of the locking lever 61, and the locking lever 61 is pressed down against the locking lever spring 64.

For this reason, the buffer lever 60 is connected to the locking lever 6.
Since the lock by the first cam portion 61a is released, the cam portion 61a is rotated clockwise by the urging force of the buffer spring 62 and hits the stopper portion 65 provided on the mirror box.
Position 1 of the main mirror receiving plate 11 indicated by a two-dot chain line in the figure
Reference numeral 1 'indicates a position in a mirror down state. In this state, the mirror contact portion 60a of the buffer lever 60 is located above the adjustment dowel 6.

Here, the opening / closing operation of the sub-mirror receiving plate 16 which is performed simultaneously with the raising operation of the main mirror unit will be described with reference to FIGS. 19 and 20.

FIG. 19 is a view of the main mirror unit when the mirror driving unit is in the state shown in FIG. 5, as viewed from the sub-mirror driving plate 17 side. As the main mirror unit moves up, the link 20 and the main mirror receiving plate 1
As the angle of 1 decreases, the sub-mirror driving pin 20a of the link 20 gradually pushes the sub-mirror driving cam 17a of the sub-mirror driving plate 17. As a result, the sub-mirror receiving plate 16 rotates in a direction to close with respect to the main mirror receiving plate 11.

In the mirror-up state, the sub-mirror driving pin 20a is connected to the sub-mirror driving cam 17 as shown in FIG.
a of the sub mirror receiving plate 16
Is completely closed.

The cam top portion 17b is formed in an arc shape centering on the hinge 14a of the main mirror unit, and even if a slight error occurs in the position of the main mirror receiving plate 11 (angle with the link 20). It is not affected.

Next, the operation of the mirror drive unit and the buffer mechanism during the lowering operation from the mirror-up state to the mirror-down state will be described in detail with reference to FIGS.

FIG. 8 shows the mirror driving unit when the lowering operation of the main mirror unit is started. The mirror lowering operation is started by energizing the electromagnet 44 and rotating the tension release lever 40 counterclockwise as in the mirror raising operation. However, unlike when the mirror is raised, the contact portion 40b of the tension release lever 40 rotates the down tension lever 36. For this reason, the tightening portion 36a of the down tightening lever 36 is
Of the first mirror lever 32
Is immediately returned to the position in the mirror-down state by the urging force of the mirror lever spring 45.

Therefore, the light shielding plate 52 disengaged from the light shielding plate driving pin 32b of the first mirror lever 32 also immediately returns to the mirror-down state by the urging force of the light shielding plate spring 46.

FIG. 9 shows the state of the buffer mechanism when the light shielding plate 52 returns to the position in the mirror down state. In this state, the locking lever 61 released from the action of the locking release pin 52c rotates clockwise by the urging force of the locking lever spring 64, but the holding portion 61b is
The movement is stopped by abutting against the outer peripheral surface 60b.

The urging force of the locking lever 61 is
, The stop position of the buffer lever 60 is not affected.

The second mirror lever 33, which has lost its support in the mirror driving unit, starts rotating by the urging force of the mirror down spring 37, and the main mirror unit is raised by the driving urging force received from the second mirror lever 33. Descends in reverse order. In addition, the assist lever 39 is provided with a second mirror lever drive shaft 33 that moves in the guide groove 39c.
The posture is maintained until a reaches the hook portion 39d.

FIG. 10 shows the state of the main mirror unit and the mirror drive unit 70 immediately after the second mirror lever drive shaft 33a has passed the position of the hook portion 39d, with only a part of the members being extracted.

When the restriction by the second mirror lever drive shaft 33a is released, the assist lever 39 is rotated counterclockwise from the position 39 'shown by the two-dot chain line by the urging force of the assist lever spring 40, and the hook portion is turned. Due to the engagement between 39d and the second mirror lever drive shaft 33a, the pressing biasing force is applied to the main mirror unit immediately before reaching the position where it comes into contact with the adjustment dowel 6.

As shown in FIG. 11, when the main mirror unit reaches a position where it comes into contact with the adjustment dowel 6, the mirror driving unit is in a mirror-down completed state.

FIG. 12 shows the state of the buffer mechanism at the position of the main mirror receiving plate 11 corresponding to FIG. 10 and FIG. 13 respectively.

As shown in FIG. 10, the assist lever 39
As shown in FIG. 12, almost at the same time when the main mirror unit starts to apply the pressing biasing force to the main mirror unit via the second mirror lever drive shaft 33a (that is, immediately before the main mirror unit reaches the position where it comes into contact with the adjustment dowel 6), as shown in FIG. The main mirror unit is a mirror contact portion 60a of the buffer lever 60.
Abut.

Thus, the main mirror unit which continues to descend by receiving the driving urging force from the second mirror lever 33 and the pressing urging force from the assist lever 39 is buffered based on the urging force of the buffer lever spring 62. Lever 6
Through 0, the urging force in the up direction (collision-mitigating urging force) starts to act with a magnitude that does not hinder the descending operation. Thereafter, the buffer lever 60 is pushed by the main mirror receiving plate 11 of the main mirror unit that moves downward and rotates counterclockwise while resisting the urging force of the buffer lever spring 62.
Therefore, a part of the descending energy of the main mirror unit is absorbed. Then, as shown in FIG. 13, the cam contact portion 60 b of the buffer lever 60 engages with the cam portion 61 of the locking lever 61 near the position where the main mirror unit contacts the adjustment dowel 6. Therefore, the buffer lever 60 receives the counterclockwise moment again by the urging force of the locking lever 61, and continues to rotate counterclockwise regardless of the movement of the main mirror unit. The mirror returns to the position in the mirror down state shown in (1) and stops.

Next, the mirror drive unit 70 starts the operation of returning to the original position in the mirror-down state at a fixed time after the lowering of the main mirror unit.

FIG. 14 is a diagram showing the state of the mirror drive unit 70 during the return operation. When the tip 31e of the raising lever 31 is pushed rightward in the figure by a lever (not shown), the raising lever 31 rotates counterclockwise against the urging force of the raising spring 34. The charge pin 31b of the stowage lever 31 comes into contact with the cam portion 39b of the assist lever 39, and the assist lever 39 is moved to the assist lever spring 40.
Is rotated clockwise against the urging force of As a result, the hook portion 39d moves away from the second mirror lever drive shaft 33a.

Note that the animal power lever 31 is
Simultaneously with the return operation of No. 9, the return operation of the tension release lever 40 and the armature lever 43 is also performed by the arm-shaped cam portion 31d. Then, the standing bending portion 31 of the rotating livestock lever 31
When c reaches the tightening portion 35a of the up tightening lever 35,
Again, the livestock lever 31 is held by the up tension lever 35, and the return to the position in the mirror down state of FIG.

As described above, according to the present embodiment, immediately before the main mirror unit that moves down to the down position collides with the adjustment dowel 6, the collision mitigation urging force from the buffer lever 60 is applied to this main mirror unit. Since the energy is applied, the energy of the lowering of the main mirror unit is absorbed, and the lowering speed is reduced. For this reason, it is possible to reduce the first rebound that occurs when the main mirror unit collides with the adjustment dowel 6. Moreover, immediately before the end of the lowering of the main mirror unit, the pressing biasing force is applied to the main mirror unit via the assist lever 39 in addition to the driving biasing force. (Repetition of the decaying bouncing) can be suppressed.

As described above, according to the present embodiment, by combining the cushioning lever 60's collision mitigation action of the main mirror unit and the assist lever 39's action of suppressing the main mirror unit's slight vibration, the main mirror unit can be lowered. It is possible to effectively suppress the bouncing phenomenon accompanying the returning operation to the position.

By the way, in order to quickly absorb the energy of the main mirror unit that moves downward, it is more effective as the collision-releasing urging force from the shock-absorbing lever 60 is stronger, but it is difficult to return the main mirror unit to the down position. Not as strong. Therefore, it is necessary to devise a means for maximizing the collision-mitigating urging force.

FIG. 23 is a graph conceptually showing a change in the urging force acting on the main mirror unit in the down direction between the up position Su and the down position Sd indicated by the horizontal axis.

First, the case where the mirror down operation is performed only by the mirror down spring 37 will be considered. In this case, the urging force acting on the main mirror unit gradually decreases from the up position Su and changes as shown in the graph 82, and becomes Fd 'at the down position. Since the energy is determined by the product of the force and the moving amount, the energy applied to the main mirror unit is represented by a hatched area E1 surrounded by the line of the graph 82.

Further, the collision-mitigating urging force from the shock-absorbing lever 60 must be set within a range in which the main mirror unit reliably operates by the urging force of Fd 'and returns to the down position.

However, in the present embodiment, as shown by the graph 81 in the figure, the urging force acting on the main mirror unit is the pressing urging force from the assist lever 39 at the point of Sa immediately before the mirror down is completed. For,
It becomes Fd when the mirror down is completed. The energy applied to the main mirror unit increases by the shaded area E2, but the urging force in the mirror down direction is Fd '.
Greatly exceed. Therefore, the collision-mitigating urging force of the shock-absorbing lever 60 may be set within a range in which the main mirror unit reliably operates with the above-described urging force of Fd.

In this embodiment, the buffer lever 6
When the mirror is moved down, the stop lever 0 stops the contact with the main mirror receiving plate 11 when the mirror is completely lowered and retracts. Therefore, even if the bias of the assist lever 39 is released by the return operation of the mirror driving unit, the mirror is lowered. Only the urging force of the spring 37 ensures that the main mirror unit is held at the down position.

Further, as described above, since the biasing force of the assist lever 39 is almost inactive when the main mirror unit is moved up and down, the mirror driving mechanism according to the present embodiment operates to move the main mirror unit up and down. Without any loss of performance.

FIG. 24 is a graph qualitatively showing the effect of preventing the mirror bounce phenomenon according to the present embodiment. The vertical axis indicates the position of the main mirror unit, and the horizontal axis indicates time.
A graph B1 shows a bouncing phenomenon of the main mirror in the present embodiment, and a graph B2 shows a bouncing phenomenon of the conventional main mirror.

As can be seen from this figure, according to the present embodiment, the main mirror unit whose energy has been absorbed by the buffer lever 60 immediately before reaching the down position,
The descending speed is reduced, and the amount of first rebound after colliding with the adjustment dowel 6 is greatly suppressed as compared with the case of B2. Further, the subsequent micro-vibration also decreases due to the urging force of the assist lever 39, and the bouncing phenomenon disappears in a time t1 shorter than the time t2 until the bouncing phenomenon required in the case of B2.

In this embodiment, as described above, by suppressing the bounce of the main mirror unit, the bounce of the sub-mirror unit, which is greatly affected by the main mirror unit, can be suppressed to some extent. Therefore,
It is possible to start the focus detection and the mirror unit up operation immediately by estimating the bound disappearance time at an early time.

In this embodiment, the assist lever 3
Although 9 presses the second mirror drive shaft 33a, the present invention is not limited to this, and the hook portion 39d may be configured to directly press the main mirror drive pin 13b.

Further, the buffer mechanism including the buffer lever 60 may be provided on the mirror drive unit side.

[0092]

As described above, according to the present invention, the energy of the return operation of the movable mirror to the position where the movable mirror comes into contact with the regulating member is absorbed by the collision-mitigating biasing force, and the movable mirror immediately after the collision with the regulating member is absorbed. Not only can the first rebound be reduced, but also the micro-vibration of the movable mirror after the first rebound can be suppressed by the pressing force. Therefore, if the movable mirror supports a sub-mirror for focus detection and the like, the bounce of the sub-mirror can be effectively suppressed. Therefore, it is possible to immediately detect the focus by estimating the bounce disappearance time of the mirror at an early time, or to start the retreat operation of the mirror from the photographing optical path, thereby realizing a higher continuous shooting speed.

Since the collision mitigation means for applying the collision mitigation urging force is detached from the movable mirror after the movable mirror comes into contact with the regulating member, the movable mirror is held at a position where it comes into contact with the regulating member. Can be unimpeded. Therefore, it is possible to provide a camera capable of reliably suppressing the bouncing phenomenon without affecting the operation of the movable mirror.

[Brief description of the drawings]

FIG. 1 is a front view of a mirror driving unit of a camera according to a first embodiment of the present invention.

FIG. 2 shows the mirror driving unit (mirror down state)
FIG.

FIG. 3 is a side view showing a buffer mechanism (mirror down state) provided in the camera.

FIG. 4 is a side view showing a state where the mirror driving unit raises the mirror unit.

FIG. 5 is a side view showing a state where the mirror driving unit further raises the mirror unit from the state shown in FIG. 4;

FIG. 6 shows the mirror driving unit (mirror up state).
FIG.

FIG. 7 is a side view showing the buffer mechanism (mirror up state).

FIG. 8 is a side view showing a state where the mirror driving unit lowers the mirror unit.

FIG. 9 is a side view showing the buffer mechanism (in a state where the mirror is down).

FIG. 10 is a side view showing the mirror driving unit (during mirror down).

FIG. 11 is a side view showing the mirror driving unit (immediately after mirror down is completed).

FIG. 12 is a side view showing the buffer mechanism (immediately before the mirror down is completed).

FIG. 13 is a side view showing the buffer mechanism (the state in which the mirror-down operation is closer to completion than in FIG. 12).

FIG. 14 is a side view showing a state in which the mirror driving unit starts a return operation to a position in a mirror down state.

FIG. 15 is a side view of a mirror unit in the camera.

FIG. 16 is a side view of the mirror unit as viewed from a side opposite to FIG. 8;

FIG. 17 is a plan view of the mirror unit.

FIG. 18 is a plan view of a sub-mirror unit of the mirror unit.

FIG. 19 is a side view illustrating the operation of the sub-mirror unit.

FIG. 20 is a side view of the mirror unit (up state).

FIG. 21 is a sectional view of the mirror box when the camera is in a viewfinder observation state.

FIG. 22 is a sectional view of the mirror box when the camera is in a shooting state.

FIG. 23 is a graph showing a change in the urging force acting on the mirror unit in the down direction.

FIG. 24 is a graph illustrating the effect of suppressing the bounce phenomenon of the mirror unit.

[Explanation of symbols]

 6,7. . Adjusting dowel 11. . . Main mirror receiving plate 13b. . Main mirror drive pin 16. . . Sub-mirror receiving plate 20. . . Link 20c. . Link drive pin 31. . . Livestock lever 31b. . Charge pin 32. . . First mirror lever 33. . . Second mirror lever 33a. . Third mirror lever drive shaft 34. . . Livestock spring . . Mirror down spring 39. . . Assist lever 39a, b. . Charge cam 39c. . Guide groove 39d. . Hook part 40. . . Assist lever spring 52. . . Light shielding plate 52c. . Lock release pin 60. . . Buffer lever 60a. . Mirror contact part 60b. . Cam contact portion 61. . . Locking lever 61a. . Cam part 61c. . Arm 62. . . Buffer spring 63. . . Locking spring

Claims (3)

[Claims] 1. A movable mirror which is positioned in a photographing optical path by contacting with a regulating member during viewfinder observation is retracted out of the photographing optical path at the time of photographing, and is brought into contact with the regulating member by driving biasing force of driving means after photographing is completed. A camera for returning operation to a position, wherein the movable mirror performing the returning operation is provided with an urging force for applying a pressing force to a position contacting the regulating member in addition to the driving urging force immediately before contacting the regulating member; Immediately before the movable mirror that returns is brought into contact with the restricting member, a collision is applied to the movable mirror that has a size that does not impede the return operation of the movable mirror and that is applied to the driving urging force and the pressing urging force. A camera comprising: a mitigation means. 2. The collision mitigation means moves to a position where the movable mirror separates from the restricting member after the movable mirror comes into contact with the restricting member by a return operation, and then the movable mirror retreats outside the imaging optical path. 2. The camera according to claim 1, wherein the camera is moved to a position where it can come into contact with a movable mirror that performs a return operation. 3. The camera according to claim 1, wherein the assist unit and the collision mitigation unit operate mechanically in conjunction with the operation of the driving unit.